In a statement to ITV, Cities of London and Westminster MP Mr Field said: "In the confusion many guests understandably felt threatened and when one protester rushed past me towards the top table I instinctively reacted.

"There was no security present and I was for a split-second genuinely worried she might have been armed.

Sir Peter, whose wife Virginia – now Baroness Bottomley – was assaulted while health secretary, said if a police officer had done what Mr Field did, "would there have been a fuss? The answer is no".

But Labour's shadow women and equalities secretary Dawn Butler described the incident as "horrific" and said "so much violence does not seem justified".

One of the activists who interrupted the Chancellor's speech (Simon Dawson/PA)

She added: "I'm sure I'm not the only one who is wondering why no one intervened. So much violence does not seem justified. An investigation needs to take place as soon as possible."

Senior captains of industry and top City executives were among the invited guests to hear speeches by Mr Hammond and Bank of England governor Mark Carney.

The UK remains committed to helping women all over the world to feel safe and protected in the work they do, so they can speak freely and be part of the change we all want. My remarks at the Westminster Hall Debate on Women Human Rights Defenders. https://t.co/fmQMtXSTgV